The three-year development process of the Wii U offers a glimpse into how the Japanese videogame manufacturer comes up with its new consoles.

Around 2009, the company’s top brass started looking into the idea of creating a game machine that offered a “second screen” controller. The managers saw it as a smart solution to overcome some of what it felt were the shortcomings of the Wii — mainly that the Wii was a secondary accessory to the television and not a primary device on its own.

In an interview with the Wall Street Journal, Nintendo President Satoru Iwata said coming up with a promising idea is only the first step in the process. At that point, Nintendo sets about to create a rudimentary, homemade prototype to replicate what the game experience would be if the hardware was made.

This process can be challenging, because Nintendo’s ideas tend to be a first-of-its-kind. At the time of the Wii U’s infancy, there wasn’t a broad range of tablets to replicate the new console’s 6.2-inch touchscreen controllers.

“We have a team of people who are good at handicraft and they just go ahead and make these things,” said Mr. Iwata. “We try to imagine that if we make this hardware, this is what it should be like and we try it out.”

For the Wii U, Nintendo’s development team hooked two Wii consoles together to work as a single device. One Wii served to deliver graphics for the “main screen” or what the players using the television would see. The other Wii was meant to replicate the experience of a second screen or what people using the Wii U controller, known as the GamePad, would see.

“Everyone here is really used to making games for the Wii, so we can make a lot of very different games very fast,” said Mr. Iwata. “After you try dozens of different games, you get a good feeling or good response with a few of them.”

Mr. Iwata said some of those early games served as the basis for “Nintendo Land,” a collection of games that Nintendo will offer with the Wii U under its “Deluxe Set” for $349.

Nintendo said it doesn’t necessarily introduce new hardware to fit the videogame industry’s traditional five- to six-year replacement cycle. It launches a new hardware console when it feels like the previous machine is reaching its limit for new types of games.

According to Wedbush Securities, the Wii’s annual sales have fallen rapidly in the past few years, from a peak of 21.4 million units sold to 11.2 million in 2011. Meanwhile, unit sales of Microsoft 's Xbox and Sony PlayStation 3 have slowly climbed.

Mr. Iwata compared the process of developing the Wii U to when it made the Nintendo DS, a portable game machine introduced in 2004. The main feature of the DS was the two screens, one of which used touch technology. While that is quite common today, it was a nascent technology at the time.

To get a sense of what types of games it could create, Nintendo’s game guru Shigeru Miyamoto, who is credited with creating many of the company’s most popular games, started making games on personal digital assistants, or PDAs, to give a sense of the types of touch-based games the DS could offer.